The present invention relates to communication systems. More particularly, the present invention relates to a method and system for decoding a data burst in a communication system.
In communication systems, data is typically transmitted between a transmitter and a receiver in the form of data bursts. These data bursts may suffer transmission errors due to various factors such as noise, interference, channel fading, etc. To minimize the effect of the transmission errors, error control techniques such as Forward Error Correction (FEC) and Automatic Repeat reQuest (ARQ) are used. Specifically, each data burst may include a plurality of data blocks. These plurality of data blocks are individually encoded using FEC to obtain FEC blocks. FEC can include, but is not limited to, a block code (BC), a convolution turbo code (CTC), a convolution code (CC) or a low density parity code (LDPC).
In conventional communication systems, physical (PHY) layer of the receiver, on receiving a data burst, stores the data burst in a buffer. An FEC decoder in the PHY layer decodes each FEC block of the data burst. Thereafter, a Media Access Control (MAC) layer of the receiver performs an error check on the decoded FEC blocks. One of the examples of the error check may include, but is not limited to, Cyclic Redundancy Check (CRC). If the MAC layer determines that all the FEC blocks in the data burst are error free, then the receiver transmits an acknowledgement (ACK) or a positive-acknowledgement to the transmitter for the data burst.
Conversely, if the MAC layer determines that any decoded FEC blocks contain one or more erroneous data bits, the receiver transmits a negative acknowledgement (NACK) or a retransmission request to the transmitter. The transmitter then retransmits the data burst received in error to the receiver. The decoding process is applied again to the retransmitted data burst. The retransmission of the data burst continue either till an ACK is not received from the receiver or at least for a predetermined number of retransmissions, whichever is earlier.
This causes undue power consumption even when the data burst is not decoded correctly. For instance, the FEC decoder may decode all the FEC blocks of the data burst even if it is later determined that one or more FEC blocks are faulty. The decoding process involves a high number of computationally intensive operations and also consumes high power. Moreover, for each retransmitted data burst, the decoder decodes all the FEC blocks in the retransmitted data burst, including the successfully decoded FEC blocks of the previous transmission. This may lead to more processing time, higher power consumption and lesser throughput at the receiver end.
There is therefore a need for methods and systems for decoding a data burst in a communication system which reduces power consumption and decreases processing time.